LM34910 Datasheet, PDF (1/11 Pages) National Semiconductor (TI) – High Voltage (40V, 1.25A) Step Down Switching Regulator

February 2005
LM34910
High Voltage (40V, 1.25A) Step Down Switching
Regulator
General Description
The LM34910 Step Down Switching Regulator features all of
the functions needed to implement a low cost, efficient, buck
bias regulator capable of supplying 1.25A to the load. This
buck regulator contains a 40V N-Channel Buck Switch, and
is available in the thermally enhanced LLP-10 package. The
hysteretic regulation scheme requires no loop compensa-
tion, results in fast load transient response, and simplifies
circuit implementation. The operating frequency remains
constant with line and load variations due to the inverse
relationship between the input voltage and the on-time. The
current limit detection is set at 1.25A. Additional features
include: VCC under-voltage lockout, thermal shutdown, gate
drive under-voltage lockout, and maximum duty cycle limiter.
Features
n Integrated 40V, N-Channel buck switch
n Integrated start-up regulator
n Input Voltage Range: 8V to 36V
n No loop compensation required
n Ultra-Fast transient response
n Operating frequency remains constant with load current
and input voltage
n Maximum Duty Cycle Limited During Start-Up
n Adjustable output voltage
n Valley Current Limit At 1.25A
n Precision internal reference
n Low bias current
n Highly efficient operation
n Thermal shutdown
Typical Applications
n High Efficiency Point-Of-Load (POL) Regulator
n Non-Isolated Telecommunication Buck Regulator
n Secondary High Voltage Post Regulator
Package
n LLP-10 (4 mm x 4 mm)
n Exposed Thermal Pad For Improved Heat Dissipation
Connection Diagram
Ordering Information
Order Number
LM34910SD
LM34910SDX
Package Type
LLP-10 (4x4)
LLP-10 (4x4)
10-Lead LLP
20110902
NSC Package Drawing
SDC10A
SDC10A
Supplied As
1000 Units on Tape and Reel
4500 Units on Tape and Reel
© 2005 National Semiconductor Corporation DS201109
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